A NEW PROBABILITY MAPPING METHOD TO DESCRIBE THE DEVELOPMENT OF ATHEROSCLEROTIC LESIONS IN CHOLESTEROL-FED RABBITS

A new probability mapping method was developed to quantify the size an d location of lesions near aortic orifices. The precise location of an y part of the lesion could be compared between rabbits. Colour photogr aphs of lesions were projected onto a digitizing tablet, and coded as lesion or non-lesion. Next the orifices were warped onto a standard or ifice, and then the lesion mapped to maintain the original length and angular location of the lesion from the edge of the orifice. This meth od, unlike the previously used polar mapping method, excludes neither absent lesions nor ones which surround more than one orifice. In contr ast to other probability mapping methods it warps the orifice rather t han the artery wall containing the lesion, and so is easier to use for correlation with histological studies. The eventual aim is to use the probability maps as a tool to estimate the age of various positions o f the lesion and to identify areas for histological sampling. The meth od was used to describe the distribution of lesions in 21 rabbits fed a diet with cholesterol levels declining from 0.5% during the first we ek, to 0.25% during the next two weeks, to 0.125% for weeks 3-10, to 0 .1% for weeks 11-24. This feeding protocol produces fatty lesions whic h are transformed into fibro-fatty and fibrous lesions with time.